Processes of producing yarn



Patented June 8, 1937 PATENT: OFFICE raocassns or raonucma nan James Louis Lohrke, Thornbnry Township. Delaware County, Pa.

No Drawing. Application April is, 1935, Serial No. 10,151;

5 Claims.

the fibers to staple fibers while maintaining their substantial parallelism and the continuity of the sliver, by simultaneously or thereafter drafting the resulting silver, and by then suitably twisting such resulting" silver to produce a yarn .or a roving from which the yarn is subsequently formed. a

In our said patent, we disclose-a specific embodiment of the invention in which the reducing step, above referred to, is performed in and by the drafting of the sliver. This is an important feature of the patented invention, since we discovered that by making a continuous sliver composed of a multiplicity of substantially continuous conventional fibers grouped in substantial parallelism and drafting such a sliver, the continuous fibers could be reduced to staple fibers. We also discovered that in thus reducing the continuous fibers to staple fibers, they were broken in a haphazard manner into irregular staple lengths, and that the substantial parallelism of the fibers would be maintained. We further discovered that such haphazard breaking I would produce a proper imbrication of the staple 5 fibers so that the continuity of the sliver would also be maintained. a Inthe simultaneous breaking and drafting of the sliver of substantially continuous fibers the length of the staple fibers produced is deter- 40 mined, within limits, by adjusting the drafting mechanism.v For instance, where sets of drafting rollers are employed, the length of the staple fibers desired in the yarn is determined by what is known as setting the ratch, which is the distance between the sets of drafting rollers. The drafting mechanism is adjusted or set for the maximium length of staple fibers to be produced in the breaking operation. In this way the length of the staple fibers is varied, in the practice of our patented process, to suit the character of yarn to' be produced thereby and the steps and/or machinery thereafter employed in such production. In so practicing the process of our Patent No. 1,883,384,however, difficulty is experienced when 5 endeavoring to break the substantially continuous fibers to relatively short staple lenghs, such, for example, as are suitable for spinning on conventional machinery according to the cotton system, because ofthe fact that the setting of the ratch for such relatively short staple lengths is interfered with by the relatively large drafting rollers which are preferably used in carrying out the simultaneous breaking and drafting operation in order to apply suilicient pressure to the silver to prevent slippage of the fibers without crushing orotherwise damaging the same.

It has also been found in practicing the invention of our patent, that in the production of relatively short staple lengths for finer counts of yarn such as made by the cotton system, the fibers composing .the sliver sometimes break in bunches instead of in a haphazard manner, so that there is a lack of proper imbrication, and a tendency of the silver to draft unevenly and perhaps break down or lose its continuity.

By the present invention I overcome these difficuities, and according to it the sliver of substantially continuous or endless fibers is first tensioned, as by drafting rollers, to break the fibers to produce over-size staple lengths, that is, staple lengths substantially greater than desired for the yarn, and the resulting sliver is thereafter subjected to one or more tensioning operations, as by drafting rollers; to reduce the over-size staple lengths so that the same are not greater than, and as far as possible are substantially equal to, the staple length desired for the production of the finished yarn, the continuity of the sliver and the parallelism of the fibers being maintained throughout the successive operations.

The preferred manner of practicing the present invention is as follows:

There is first made an endlessor continuous sliver composed of a multiplicity of substantially endless or continuous fibers brought together or combined in substantial parallelism. This sliver is passed through two sets of drafting rollers, that is, sets of feed and of delivery rollers, in which the rollers of the respective sets travel at the same surface speed but the surface speed of the delivery rolle is greater than that of the feed rollers. Eac set may consist of any suitable number of rollers. The ratch of such sets of drafting rollers is suitably adjusted so as to be substantially longer than the" length of staple desired in the yarn-to be produced. As the sliver passes through these sets of drafting rollers, tension is applied to successive portions of the fibers which are of a length corresponding to the setting of the ratch, and as a result of this tension the fibers are broken to'over-size staple lengths, that is. to staple lengths substanare over-size although some staple lengths less than over-size may be produced owing to the haphazard breaking. The relative speeds of the feed and delivery rollers are preferably such that the staple fibers produced are subjected to a simultaneous drafting operation which attenuates and suitably reduces the size of the silver. The

haphazard breaking produces a proper imbrica-' tion of the staple fibers so that the continuity of the sliver is maintained. Furthermore, the substantial parallelism of the fibers in the resultin sliver is preserved. I

Thereafter, the resulting silver is passed through the feed and delivery rollers of another te'nsioning and drafting mechanism in which the ratch is adjusted so as to be substantially equal to the length of staple desired for the yarn to be produced. In this operation the over-size staple fibers are broken so that they are less than but as far as possible substantially equal to the staple length desired for the yarn. This breaking occurs in a haphazard manner as in the previous operation and hence some of the staple fibers may be shorter than the desired staple length. The simultaneous drafting further reduces the size of the resulting sliver. The continuity of the resulting sliver and the substantial parallelism of the fibers thereof, are both maintained as in the previous operation.

Following the second breaking and drafting operation, the resulting sliver is twisted in any well-known or suitable manner, as, for instance, according to the cotton system, to produce a relatively short staple, fine count yarn directl therefrom. 1

In carrying out the present invention in this preferred manner it has been found that excellent results are obtained by setting the ratch of the first breaking and drafting mechanism at about 7 inches, and by setting the ratch of the second breaking and drafting mechanism at about 3 inches. These specific settings are given. however, merely by way. of example, and are not to be construed as a limitation upon the invention.

It has'also been found that when the substantially continuous fibers composing the silver have been broken to staple fibers of over-size lengths in the first operation, the breaking in the second operation can be performed satisfactorily by drafting rollers ofa size which will not interfere with the setting of the ratch necessary to produce the relatively short staple fibers desired for the yarn.

An important advantage of the present invention is that the yarn produced by this improved processis more even, that is, of more uniform size, than relatively short staple yarn produced by the process of Patent No. 1,883,384, and has substantially greater tensile strength.

While the improved process has been described in connection with a single'sliver of substantially endless fibers, it will be understood that two or more slivers of staple fibers produced by the breaking operatlom heretofore described may be combined if desired. For example, two of the slivers resulting from the first breaking operation may be combined and the subsequent breaking operation carried out upon the sliver thus formed.

It will also be understood that the practice of the invention is not limited to the employment of two breaking operations as disclosed in connection with the preferred method herein described, but it may be carried out in more than two operations so long as the endless fibers are first broken adage-1o to over-size staple lengths and the over-size staple lengths are subsequently broken to staple lengths not greater than the staple length desired in the yarn.

What I claim is:

1. In the process of producing yarn from a silver composed of a multiplicity of substantially continuous fibers grouped insubstantial parallelism, while maintaining the substantial parallelism of the fibers and the continuity of the silver, applying tension to successive portions of said fibers to progressively break the fibers to over-size staple length, and thereafter applying tension to the over-size staple lengths thus produced to break the same to staple fibers having a length not greater than that desired in the yarn.

2. In the process of producing yarn from a silver composed of a multiplicity of substantially continuous fibers grouped in substantial parallelism, while maintaining the substantial parallellsm of the fibers and the continuity of the silver, applying tension to successive portions of the fibers, having a length substantially greater than the maximum length of the staple desired in the yarn, to progressively break the fibers in a haphazard manner, and thereafter applying tension to the over-size staple fibers thus produced to break the same to staple lengths not greater than desired in the yarn, and drafting the resulting sliver. I

3. In the process. of producing yarn from a sliver composed of a multiplicity of substantially continuous fibers grouped in substantial parallelisn, while maintaining the substantial parallelism of the fibers and the continuity of the sliver, applying tension to successive portions of said fibers to progressively break the same to over-size staple lengths and simultaneously draft the sliver,. and thereafter applying tension to such over-size staple lengths to break the same to staple fibers of not greater than the length desired in the yarn and to simultaneously draft the resulting sliver.

4. The process of producing yarn which consists in making a continuous sliver composed of a multiplicity of substantially continuous fibers grouped in substantial parallelism, passing the silver through a group of drafting rollers having a ratch substantially greater'than the maximum length of staple desired in the yarn to thereby break the fibers to staple fibers some of which are over-size and to draft the sliver, and thereafter passing the resulting sliver through-a second group of drafting rollers having a ratch substantially equal to the length of the staple desired in the yarn thereby to break the over-size staple fibers and to draft the sliver, while main taining the substantial parallelism of the fibers and the continuity of the sliver.

5. In the process of producing yarn from a continuous sliver composed of a multiplicity of substantially continuous conventional fibers grouped in substantial parallelism, reducing the fibers to staple fibers and drafting thesliver while maintaining both the substantial parallelism of the fibers and the continuity of the sliver, by passing the sliver through a plurality of groups of drafting rollers, the initial group having a ratch substantially greater than the maximum length mum length.

JAMES LOUIS LOHRKE. 

